In general, fabric articles can be cleaned using water as the primary medium with, additionally, surfactants and other cleaning agents for enhancing the cleaning performance.
However, some laundry articles cannot be safely cleaned with water. For these, a dry cleaning process may be used wherein a cyclosiloxane dry cleaning solvent is the primary medium. Dry cleaning is, however, only available in specialised outlets and, usually, consumers have to bring and pick up their clothes, which is not convenient.
In this connection, some proposals have been made towards an in-home dry cleaning process, i.e. a dry cleaning process for relatively small wash loads suitable for use in domestic environments.
However, the use of organic cyclosiloxane dry cleaning solvent in domestic environments requires a more stringent approach regarding safety and ease of use.
Domestic environments are usually well adapted for aqueous washing; water is available from a tap and can be discharged to a sewer after washing. Evidently, this will be more complicated with cyclosiloxane dry cleaning solvents. Fresh solvent needs to be supplied to replenish lost solvent. The supply of fresh solvent will probably be carried out via cylinders which need to be purchased separately from time to time. Furthermore, for environmental and safety reasons the dry cleaning machine will probably have to be designed as a closed system. This is to retain substantially all of the solvent so as to minimise losses into the environment. In addition, the whole process of adding fresh solvent and collecting used solvent will also have to meet such stringent environmental and safety requirements.
Various dry cleaning systems are known in the art.
For instance, WO-A-01/94678 discloses fabric article treatment processes to be carried out in a domestic appliance, which may preferably include a washing step wherein a lipophilic cleaning fluid, such as a siloxane, is present as the predominant fluid. However, this document does not disclose appliances or machines that incorporate effective safety measures, in particular safety measures that reduce the risk involved when using lipophilic fluids having a flash point, such as cyclosiloxanes.
Another type of dry cleaning system is disclosed in WO-A-01/94675. This document describes a dry cleaning apparatus and method for fabric treatment, that are safe for a wide range of fabric articles, minimise shrinkage and wrinkling, and can be adapted to a cost-effective use in the consumer's home. In said method a lipophilic cleaning fluid is used, which can include linear and cyclic polysiloxanes, hydrocarbons and chlorinated hydrocarbons. Preferred lipophilic solvents are non-viscous, and include cyclic siloxanes having a boiling point at 760 mmHg of below 250° C.
However, it has been found to be less safe to use a non-viscous cyclosiloxane dry cleaning solvent under all circumstances. For practical reasons it is indeed desirable to use a non-viscous cyclosiloxane dry cleaning solvent having a viscosity of no more than about 5 cSt under normal operating conditions. Under high-risk conditions, however, it is less safe to operate a dry cleaning system comprising a solvent with a viscosity of no more than about 10 cSt.
Furthermore, US-A-2003/0226214 discloses a dry cleaning system containing a solvent filtration device and a method for using this system. The lipophilic solvent used herein is preferably inflammable. It is also preferred that said solvent has a relatively high flash point and/or a relatively low volatile organic compound (VOC) characteristic, whereby it is also mentioned in this document that suitable lipophilic fluids are readily flowable and non-viscous. However, it has been found that under high-risk conditions it is less safe to apply such a non-viscous and readily flowable fluid in a dry cleaning system.
In view of the foregoing, it is concluded that the dry cleaning systems of the prior art leave to be desired in that the solvent viscosity is generally such that in case of a spill the solvent could easily cover a large surface area in a residential home, possibly even covering multiple floors in the home.
In case of an increased temperature event, a rupture in the dry cleaning system could easily lead to spillage of the cyclosiloxane dry cleaning solvent, such as cyclosiloxane, which could considerably increase the risk of fire.
It is, therefore, an object of the present invention to provide a novel dry cleaning system that addresses one or more of the drawbacks mentioned above. More in particular, it is an object of the invention to provide a dry cleaning system that comprises elements for improving the safety of said system. It is also an object to find a safe dry cleaning method that can be carried out in said system.
It has now surprisingly been found that these objects can be achieved with the dry cleaning method and system of the present invention.